This invention relates to liquid sampling apparatus. There is disclosed below such apparatus for obtaining samples of water from a mixture of oil and water contained in oil tanks, especially the tanks of ocean going oil tankers, corresponding shore tanks, and underground fuel storage tanks, where access to the base of the tank is difficult to obtain. The invention is also applicable to other liquid sampling environments, including sampling from storage tanks and vats generally, the sea bed, rivers and other waterways, reservoirs and wells, and analogous applications.
There is a need to obtain water samples from the water which is often found to be mixed with the oil in the tanks of oil tankers. Such water samples are used for analysis purposes. The analysis enables data to be obtained which may permit identification of the source of the water.
There is disclosed in U.S. Pat. No. 3,680,389 (Binkley) sampling apparatus for a waste disposal system, particularly for use at an off-shore location. A sampling vessel has upper and lower valves actuated by a projecting foot. The foot is connected by an actuating rod 43 to the two valves to actuate same, and thus they both open upwards. Coiled compression springs 56,57 hold the valves in their closed position. An annulus 33 is provided to house heavy ballast material whereby the weight of the apparatus can be sufficient to enable the valves to be opened through the medium of foot 58 and rod 43.
There is a need for improvements with respect to the above-mentioned prior art in several respects. Firstly, there is a requirement for sampling apparatus which is smaller and lighter in weight and thus easier to handle than the prior art. In particular, it would be beneficial if the need for ballast weight could be avoided. Secondly, with regard to the application of the sampling apparatus to situations in which it is desired to sample liquid at a well defined depth, and perhaps varying depths, close to but not necessarily at the bottom of an oil tank, or on the sea bed, there is a need for means whereby this can be achieved. Other desirable refinements relate to the general construction of such a device, its economy of manufacture and ease of use.
Accordingly, a general aim of the invention is to provide liquid sampling apparatus having improved means for operating the valves thereof, particularly means whereby the load required to open the valves is reduced.
Another aim of the invention is to provide liquid sampling apparatus having means whereby the depth at which the valves are opened, can be adjusted.
Still another aim of the invention is to provide liquid sampling apparatus which can be made in a form which is lighter in weight, less bulky, and more readily utilised.